Ethylene glycol is an important chemical raw material and strategic material in China, which is used to produce polyester (which can be further processed to produce terelyene, PET bottles and thin films), explosives, glyoxal, and can also be used as antifreeze, plasticizers, hydraulic fluids, solvents and the like. In 2009, the import quantum of ethylene glycol in China was over 5.80 million tons. It is predicted that in 2015, ethylene glycol demand of China will reach 11.20 million tons; while the production capacity will be about 5 million tons, and the supply and demand gap will still be 6.20 million tons. Therefore, there is a good market prospect for the development and application of new production technology of ethylene glycol in China. Internationally, ethylene glycol is mainly obtained by hydration of ethylene oxide which is mainly produced by oxidation of ethylene generated from petroleum cracking. In view of the current state of China's energy source structure of being rich in coal, lack in oil and gas, and the crude oil price being kept at a high level for a long time, the process for producing ethylene glycol from coal as a new technique in coal chemistry industry is the most practical choice of the coal chemistry industry in the future, because it can ensure the national energy safety and make full use of the coal resource in China.
At present, the relatively mature technology in China is a complete set of technology containing CO gas phase catalytic synthesis oxalate ester and catalytic hydrogenation synthesis of ethylene glycol from oxalate ester, developed by Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences. In early December 2009, the coal-to-ethylene glycol project of GEM Chemical Company, Tongliao, Neimenggu with a yearly output of 200 thousand tons, has been successful in getting through the entire process in the first-stage project and produced a qualified ethylene glycol product, which is the world first industrial demonstration device, attracting industry attention. However, due to relatively more industrial units, high requirement of industrial gases purity, usage of noble metal catalysts in the process of oxidative coupling, and utilization of nitrogen compounds with potential environment pollution, the technology process has been restricted in economic efficiency, environmental protection, energy-saving performance and further industrial scale-up.
Recently, methyl methoxyacetate, as an important organic intermediate, has attracted wide attention. It can be prepared by gas phase carbonylation of methylal (Angew. Chem. Int. Ed., 2009, 48, 4813-4815). Methyl methoxyacetate can be hydrogenated to prepare ethylene glycol monomethyl ether and ethylene glycol monomethyl ether can be hydrolysed to prepare ethylene glycol. In CN104119228A, the above content has just been mentioned in Background and there are no any informations on the detailed steps and process for preparing ethylene glycol by hydrolization of ethylene glycol monomethyl ether.